A cry for a savior, a wish to survive
by JustAPersonWithTime
Summary: A cry for a savior, a wish to survive. That was all it took for Shirou Emiya to appear. A hero is wished into a world before his time to fight against the demons of humanity. Rise Hero, for the sake of others falls upon your shoulders. {One-Shot} Spoiler Alert! This covers the Dimensional Infinity Fortress Arc. (Note: Thanks to The Indominator for pointing it out.)


**Kimetsu x Fate**

**(One-Shot)**

**This was kind of stuck in my mind. I would love a Kimetsu x Fate/Stay Night fanfiction, but I haven't seen any. This will most likely stay a one-shot for the time being as I'm currently working on my other fanfiction Awaken O Sword. Anyways this one shot was meant to be a breather from AOS. Five chapters in six days is kinda tiring so I'm going to do things like this as breaks. Thanks!**

**Beta: SilverZekrom**

**Summary:**

**A cry for a savior, a wish to survive. That was all it took for Shirou Emiya to appear. A hero is wished into a world before his time to fight against the demons of humanity. Rise Hero, for the sake of others falls upon your shoulders. {One-Shot}**

Tanjiro knew there was no avoiding this blow. Even after decapitating Akaza, the body was still able to function. It's leg came up to strike and Tanjiro closed his eyes. Giyu was too injured, and unarmed. His blade had been snapped in half and the enemy was just too strong. This was the end for him.

_"I wish I could have saved them. I'm sorry Nezuko, Urokodaki. I've failed you both"_

With that, the fate of the world was rewritten. His single wish to live was answered.

As the blow came closer, Tanjiro had expected pain before dying. Instead there wasn't any. Hesitantly, he opened his eyes, only to see a silhouette of a man in front of him. With twin swords of pure white and black, the man had halted the kick from Akaza's body. In an instant the leg that had struck out was instantly severed. It had been a clean cut, where the blade had cut through even the bones of the demon. Something like that was almost in humanly possible, yet the person in front of him had done it. Staring in wonder, Tanjiro could think about how strong the person protecting him was. He then blacked out from the pain.

Shirou was confused. One moment he was preparing to go on a Dead Apostle hunt, next he was transported into an attack by a headless man? Obviously he had heard the call for help, but he definitely didn't expect to be teleported to it instantly. It seemed that Zelretch might have been messing around again. Sighing he knew this may have been a prank, but even so, as a hero of justice, he would protect those who couldn't.

In front of him was a headless man, and to the right was another. That person had similar clothes to the one behind him, and was in terrible shape. Shirou was surprised he was still standing, but that's besides the point. Facing his opponent, Shirou readied himself in Archer's stance. Waiting for the next move, Shirou eyed his opponent. The head was nearby, but there was a stub of a sword sticking out of it. Just as he was about to trace it, the headless body moved. It seemed to have regenerated it's leg while he was distracted. Whatever. Swinging both swords in the shape of an x, Shirou struck both arms with the married blades. Even if the arms were quite sturdy, his blades still cut through them. He was about to continue pushing when he noticed his opponents leg.

**Technique Deployment : Leg Style - Flowing Light Flash**

Immediately multiple kicks were landed onto Shirou's abdomen. Shirou gasped in pain. Even if he had reinforced himself, the armor he had on was almost immediately crushed from the amount of kicks landed at that time. "Strong!" thought Shirou. It almost reminded him of a servant level attack. Reversing his grip on his swords, Shirou planned to remove both legs, only for the both arms to appear in his face.

**Technique Deployment : War Style **

Immediately, the punch created a large shockwave almost knocking Shirou out. It was like getting blasted in the face by Invisible Air. Luckily he was prepared and was able to mitigate most of the damage. It still hurt though. "You want to use martial arts? I'll show you some"

**Six Grand Opening - Elbow Upthrust**

Using his elbow, Shirou launched a devastating strike into Azuka's chest, immediately caving it in. He followed up with Kanshou and removed the headless man's arm, only to be punched by the other one. Backing up Shirou took this time to analyze his opponent. Using Bajiquan against a martial artist wasn't the smartest move, but he had to gain space. By now his opponent had almost full regenerated. His head was still missing and few things but he was almost fully healed.

"Another swordsman huh? You don't wear the traditional Demon hunter clothings, so who are you?" Shirou didn't reply but instead decided to trace the shattered sword on the floor. The knowledge gained surprised him. It was a Nichirin Blade, otherwise known as the color changing sword. It's main purpose was to kill demons, and it was wielded by the man named Giyu Tomioka. Staring back, he looked at Giyu he asked, "How are you holding up?" Giyu didn't respond to him. It seemed he blacked out from the pain as well.

"My name is Akaza, red swordsman. I can tell you're strong, so fight me!" With that the battle between the demon and the hero continued. Twin swords fought against bare hands, as Shirou continued to block and parry Akaza. Chances were the married blades weren't going to cut it, so Shirou threw them.

"Throwing your swords? Foolish!" Akaza knocked them aside and rushed in. "Going to use that stance again, right? Like hell I'm falling for that." He then jumped up in to the air.

**Technique Deployment : Crush Style - Willow of a -**

He was interrupted by a blade flashing forwards. "Impossible" Akaza thought, as a newly formed katana flew at him. Canceling his attack, he braced himself as the blade started to cut through him. Halfway through the blade was logged into his body. Now was his chance! Preparing to strike again, Akaza raised his hands to chop forward, only to realise one thing. There wasn't just one sword, but rather a dozen. The martial artist was immediately thrown backwards, skewered by dozen nichirin blades.

Shirou turned to face the boy, no young man, and began to assess his injuries. Surprisingly, the damage on the outside was quite minimal, rather the damage was more internalized. It seems that Akaza's martial arts was pretty similar to Kotomine's Bajiquan. But back to the situation at hand, Shirou needed something to heal the young man in front of him.

Diving into Unlimited Blade Works, Shirou immediately went into high gear to find a noble phantasm that had healing abilities. After looking over a few dozen, one came into mind. Avalon was good, but it required a decent amount of prana for it to function correctly. Sighing he prepared himself. Even if the real Avalon was integrated within himself, he still needed prana to trace a copy of it.

"**Trace On**"

**I am the bone of my sword**

**Steel is my body, fire is my blood**

**I have created over a thousand blades,**

**AVALON!**

Golden light began to appear as the sheathe started to materialize. Shirou realised that even if the sheathe was able to manifest, without Saber, it's healing would be at best one tenth of its original strength. Even still, it would be enough to keep the one in front of him alive.

"Hey, … " Shirou turned his head. It seemed that Giyu had woken up. "You killed that demon?" Shirou nodded. "Alright." The room fell silent as neither person had anything to say. Surprisingly it was Giyu who broke that silence. "How is he? Tanjiro I 's the person in front of you." Shirou didn't reply. "That bad huh… Will he make it?" Shirou swallowed. "He'll make it." Giyu slumped over. "Thank the gods…" With that, he stumbled over to where Tanjiro was.

He had grown so much, from the kid who was begging him not to kill his sister, to a demon slayer on par with that of a pillar. This kid had the potential to become one of the strongest, and that made Giyu smile. Ubuyashiki was right, things were going to change this century. The introduction of this red swordsman only reinforced this fact. The dance of the fire gods shall pave the way for the demon's full eradication.

Snapping out of his musing, he noticed movement behind the red swordsman. There was something out in the hallway scuffling about. Reaching for his sword, he realised it wasn't there. All he could do was slightly nudge the red swordsman and hope he realised that there was something there. Luckily he did. Dashing forwards the hallway, Shirou turned the corner. Giyu noticed he had grabbed something, but didn't see until he brought it back in with him.

"A crow… That's Tanjiro's crow! He might have a message, here hand him over." Shirou passed the bird that he had grabbed over to Giyu. There in it's talon was a scroll, rolled up. Giyu tucked it in Tanjiro's shirt. "I'll remind him later. Thank you" Shirou nodded. Standing back up, he turned to the hallway. He said, "I'll be off, something doesn't smell right, there are other people to be saved.

Looking forwards, he was about to headout when he felt the air change. It felt rather cold, the tense feeling in the air permeated.

**End style ...**

Shirou immediately sent his prana towards Avalon, causing the sheathe to shine brightly. Giyu ran towards the body of Tanjiro, doing his best to shield it from the upcoming attack. Akaza jumped up and grinned as he prepared his strongest attack.

**Chaotic Blue Metal Afterglow**

The room that the four were in was instantly almost destroyed. The room was blown apart as miniature shock waves were thrown about without a care. Blows were sent everywhere, and almost nothing was left unscathed. Among the debris stood one figure, a notable red cloak, with a bright yellow spear. Gae buidhe, was its name, a spear with a passive ability to almost nullify even the strongest regenerative abilities. It's a cursed spear that causes all injuries to regenerate at a human's pace. That meant that Akaza's and even all of demon's abilities to be almost useless in the face of that spear.

Shirou took note of the two warriors who were in the corner of the room. Avalon had done its job protecting them. Giyu was still awake, and he nodded at him. The bird was fine as well, although taking another glance at it, he realised there was a piece of paper with an eye on it. Tracing it, he realised that it was meant to rely information to its users when it came to mapping out the area. The bird cawed at him, "Good! You are different! Please help the others, they are in danger" Shirou smiled and picked up the bird. "Then lead the way, for this hero of justice." A bird and a swordsman, left the water pillar with Tanjiro to help the others who were in dire need of help.

A single wish was all that was needed to change destiny. A cry for someone to save him had called upon a hero of unmatched potential. That hero would help lead the demon slayers to victory upon the demons, and help revive the breath of the sun users. Eventual with time, he would disappear, a name only known to those who used to slay demons. His name was Shirou Emiya, a true hero of justice.

**Anyways that's the end for the one shot. Maybe if I finish Awaken O Sword, I might come back to actually make a story of this. I really wanted a FSN x Kimetsu fanfic so I decided to put this out. I might make a second part, where Shirou participates in the Upper moon one fight, but who knows? Anyways I hope you enjoyed this one-shot and I wish you a wonderful day.**


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